The present invention is directed to a method of interfacing a fixed wireless terminal (FWT). A fixed wireless terminal, as disclosed in commonly-owned U.S. Pat. No. 4,658,096, which patent is incorporated by reference herein, couples a standard land-line telephone, such as a POTS telephone, facsimile machine, and the equivalents thereof, to a cellular transceiver, whereby the land-line telephone may be used for making and receiving calls over the cellular network.
The FWT device emulates Telco Central Office (CO) functions in order to connect the land-line telephone to the cellular wireless network. The FWT provides telephone service using standard telephone devices in places where landline service is either not available or is less economically advantageous.
While the predominant use of an FWT is to couple a standard POTS-type telephone to a cellular wireless network, an FWT has been used for coupling the FWT to a trunk port or analog port on the CO-side of a PBX/PABX (Private Branch Exchange or Private Automatic Branch Exchange), in order to thereby provide wireless service for the PBX or PABX over the cellular network. However, this use of the analog port of the PBX or PABX often requires considerable modifications to the FWT hardware and/or re-programming of the software of the PBX/PABX to accommodate this connection. However, in contrast, connection of a conventional analog telephone device (such as a POTS telephone device) to the extension side of the PBX/PABX usually requires no modifications other than provision of a usually already-existing analog extension port.
An FWT cannot be connected directly to the extension side of the PBX/PABX, because both the FWT and the PBX/PABX provide CO-side connections; i.e., they are both designed to provide loop current and ring signal for the land-line telephone instrument. Connecting the FWT directly to the PBX/PABX at the extension side of the PBX/PABX, would result in damage to one or both of them.
It is, therefore, beneficial and desirable to provide an apparatus which can reside between the common FWT and the PBX/PABX to accommodate the existing interfaces, whereby the FWT may be coupled to the extension side of the PBX/PABX, whereby any of the land-line telephones connected to the PBX/PABX may also be used to make calls or to receive calls over the cellular wireless network by means of the FWT coupled to the extension side of the PBX/PABX. These connections may be made in multiple, in order to provide multiple wireless lines.
It is, therefore, the objective of the present invention to provide a method and apparatus for interfacing a fixed wireless terminal (FWT) to the extension side of a Private Branch Exchange (PBX) or Private Automatic Branch Exchange (PABX), whereby the PBX/PABX may make or receive calls over the cellular wireless network via a fixed wireless terminal, such as that disclosed in commonly-owned U.S. Pat. No. 4,658,096.